Salix Pharmaceuticals (NASDAQ:SLXP) has entered into an agreement to acquire Santarus in a cash deal valued at $2.6 billion, the company announced after the close of the markets Thursday.

Raleigh-based Salix, a specialty pharmaceutical company focused on gastrointestinal treatments, said it will acquire all of the outstanding common stock of Santarus at the price of $32 per share, a 37.9 premium over the company’s Thursday closing price of $23.20.

San Diego-based Santarus also has gastrointestinal products as well as endocrinology drugs. The acquisition has already been approved by the boards of directors of both companies.

“We believe our acquisition of Santarus and the combined assets of our two companies should create a larger, even stronger Salix that will be better positioned to provide solutions for gastrointestinal disorders to patients and healthcare providers,” Salix CEO Carolyn Logan said in a statement. “We look forward to entering 2014 and beyond as the largest U.S. gastroenterology-focused specialty pharmaceutical company.”

Salix’s top selling drug is Xifaxan, a drug approved to treat treat traveler’s diarrhea as well as hepatic encephalopathy, a a brain disorder associated with severe liver disease. Xifaxan generated $165.9 million in third quarter revenue, a 20 percent increase compared to the same period in 2012.

Santarus’ top drug is Glumetza, a drug that used with diet and exercise improves glycemic control in adults with type 2 diabetes. Glumetza produced $45.6 in third quarter sales, a 6 percent year over year increase.

The companies expect to close the transaction in the first quarter of 2014. Salix plans to finance the deal with $800 million cash on hand and $1.95 billion in committed financing from Jefferies LLC. Jefferies LLC also has committed to provide an additional $150 million revolving credit facility.

Salix posted on its website the following statement, attributed to Logan:

“At Salix, we work hard every day to meet the current and anticipated needs of patients and healthcare providers. We are excited about the opportunity to drive this mission forward and announced today our intention to purchase Santarus, Inc., a specialty biopharmaceutical company focused on providing gastroenterology products and other select specialties. Both Salix and Santarus share a commitment to integrity, ethics, teamwork, accountability and innovation. Through this acquisition, we will expand our ability to reach more patients and provide the additional products they need. We are excited to create a new company with greater scope and impact than either company could offer independently. This expansion is transformational for Salix, and I want to thank our employees and the employees at Santarus for their commitment and hard work that helped make this possible.